<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Hello World</title>
  <script src="https://unpkg.com/vue"></script>
</head>

<body>
  <div id="root"></div>
  <script>
    Vue.createApp({
      template: '<div>Hello World-{{count}}</div>',
      data() {
        return {
          count: 1
        }
      },
      mounted() {
        console.log('1');
        setInterval(() => {
          this.count += 1
        }, 1000);
      },
    }).mount('#root');
  </script>
</body>

</html>